Isomerization catalyst requires a continuous injection of chlorides to maintain the acid sites activity at a rate of 150 wppm of combined feed to isomerization reactors such as in UOP PENEX™ processes. The chlorides injected to the isomerization reactors result in the presence of hydrogen chloride and/or other chlorinated compounds in the gaseous and liquid effluents obtained from the isomerization unit. As is known in the art, these compounds inevitably lead to the corrosion of the facilities, formation of deposits or salts based on chlorine, and/or accelerate contamination of catalysts which might be located downstream of the isomerization unit. Thus, it is important to eliminate all traces of hydrogen chloride or other chlorinated compounds from these effluents.
Typically, such chlorides are scrubbed with a caustic solution in a net gas scrubber (NGS) before sending off gases to a fuel gas header or alternate destinations. This requires large amounts of caustic consumption on a continuous basis and refiners want to reduce the treatment cost of spent caustic. Caustic handling and treatment is an environmental concern and is cost intensive.
It is desirable to provide improved processes and apparatus for efficiently handling the chlorine injected into the isomerization process and reducing net chloride consumption. Further, it is desirable to reduce caustic consumption in the overall process, thereby decreasing associated costs.
Accordingly, the present Applicant, in U.S. patent application Ser. No. 15/813,057, filed Nov. 14, 2017 (the entirety of which is incorporated herein by refenced), provided processes and apparatuses which utilized an absorbing vessel for removing chlorides from the isomerized effluent with a portion of the isomerization feed stream.
While effective for its intended purposes, the disclosed processes used various pieces of equipment to chill or otherwise cool the feed stream before absorbing chlorides. Accordingly, it would be desirable to provide processes for absorbing chlorides from the isomerized effluent with a portion of the isomerization feed stream which do not require cooling or chilling equipment. Other desirable features and characteristics of the present subject matter will become apparent from the subsequent detailed description of the subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the subject matter.